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Soil-transmitted Helminths (Intestinal Worms)

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What's the Problem?

Soil-transmitted helminths are more commonly known as intestinal worms, and are the most common parasitic infections worldwide. These infections are caused by three kinds of worms: roundworms, whipworms, and hookworms, which infect over 1 billion people worldwide. Infection rates differ by country but can be as high as 95% in some areas.

Intestinal worms are usually caused by swallowing eggs from contaminated soil or by larvae that penetrate the skin when soil is walked on barefoot. Contamination occurs through human fecal matter that contains worm larvae and is then mixed in the soil. Once infected, individuals usually have no symptoms. However, infection can contribute to anemia, vitamin A deficiency, malnutrition, impaired growth, delayed development, and intestinal blockages.

Who's at Risk?

Most intestinal worm infections occur in rural areas of sub-Saharan Africa, the Americas, China, and east Asia. These infections occur more often in developing countries because inadequate sanitation, and lack of clean running water and drinking water increase the risk for soil contamination. Pre-school and school-aged children, adolescent girls, and women of childbearing age are more likely to have symptoms.

Can It Be Prevented?

Yes. Intestinal worm infection can be treated with a single dose of medication for mild or moderate cases. However, infection can be prevented altogether by increasing the availability of water for personal hygiene, improving sanitation, washing food properly, and by avoiding the use of human feces as fertilizer.

The Bottom Line

Intestinal worms are the most common parasitic infection and infect over 1 billion people worldwide. Symptoms vary in presentation and severity but, once diagnosed, treatment is relatively quick and inexpensive. Efforts at prevention can greatly decrease the number of new infections by promoting better hygiene and sanitation practices.

Case Example

Yixin is a 16-year old girl living in Southeast Asia who is preparing for her wedding to Wei. Her family owns a small farm and all the time that she does not spend preparing for her wedding is spent helping her family with chores around the farm. One day she feels very faint and starts feeling some stomach pains. As her wedding approaches and her symptoms don’t get any better, her mother takes her to the clinic to try and figure out what is wrong. The doctor diagnoses her with anemia, which is causing her dizziness, as a result of infection of intestinal worms. He prescribes her medicine to clear up the infection, recommends she increases the iron in her diet, wash her food properly, and tells her that she should always wear some form of shoes when she is working outside on the farm. Yixin follows the doctor’s instructions and is completely well by the time of her wedding.